Artificial-horizon gyroscope

ABSTRACT

1. AN ARTIFICAL HORIZON GYROSCOPE, COMPRISING A FRAME, AN ATTITUDE GIMBAL AND ROLL-AXIS BEARING MEANS SUPPORTING SAID GIMBAL ON A ROLL AXIS IN SAID FRAME, SAID BEARING MEANS HAVING A GENERALLY CENTRAL PASSAGEWAY THERETHROUGH, DISPLAY MEANS INCLUDING ROLL-INDICATING MEANS CONNECTED VIA SAID BEARING MEANS TO INDICATE MOTION OF SAID GIMBAL IN ROLL, A GRYO ROTOR ASSEMBLY AND BEARING MEANS SUPPORTING THE SAME ON A PITCH AXIS IN SAID GIMBAL, SAID DISPLAY MEANS INCLUDING PITCHINDICATING MEANS HAVING A PITCH-TRANSMITTING LINKAGE CONNECTION TO SAID ROTOR ASSEMBLY VIA THE PASSAGEWAY IN SAID ROLL-AXIS BEARING MEANS, SAID LINKAGE INCLUDNG A TRANSMITTING ARM PIVOTALLY SUPPORTED BY SAID GIMBAL ON A PIVOT AXIS LOCATED BETWEEN SAID PITCH-AXIS BEARING MEANS AND THE PASSAGEWAY OF SAID ROLL-AXIS BEARING MEANS, SAID ARM EXTENDING THROUGH THE PASSAGEWAY AND SUPPORTING SAID PITCH-INDICATING MEANS, THE OPENING OF SAID PASSAGEWAY BEING SUCH IN RELATION TO SIZE AND LOCATION OF SAID ARM AS TO PERMIT PIVOTED MOVEMENT OF SAID ARM THROUGH A RANGE OF DIRECT PITCH-TRANSMITTING CONNECTION TO SAID ROTOR ASSEMBLY CORRESPONDING AT LEAST TO A LIMITED PITCH   RANGE, AND SAID LINKAGE INCLUDING LOST-MOTION CONNECTING MEANS OPERATIVE TO POSITION SAID TRANSMITTING ARM AND SAID PITCH-INDICATING MEANS IN ACCORDANCE WITH PITCH MOTION OF SAID GIMBAL WITHIN SAID LIMITED PITCH RANGE AND TO HOLD A MAXIMUM DISPLACED POSITION OF SAID PITCH-INDICATING MEANS FOR GIMBAL-PITCH MOTION BEYOND SAID RANGE.

United States Patent [191 Owens et a1.

[ 1 ARTIFICIAL-HORIZON GYROSCOPE [76] inventors: Frederick J. Owens; Jerry B.

Bishop, both of Wichita, Kans. [73] Assignee: Aerssonic Corporation, Clearwater,

V Fla 1 [22] Filed: Mar. 8, 1971 21 Appl. No.: 122,055

[52] U.S. Cl. 33/329 [51] Int. Cl G0lc 19/44 [58] Field of Search 33/204, 329, 328

[56] References Cited UNITED STATES PATENTS 2,485,552 10/1949 Aumuller 33/204 C 2,489,294 11/1949 Kenyon 33/204 C 2,524,745 10/1950 Adkins 33/204 C 3,039,200 6/1962 Vibert 33/204 C FOREIGN PATENTS OR APPLICATIONS 877,780 9/1942 France 33/204 C 1,034,135 6/1966 Great Britain. 33/204 C 850,087 9/1939 France 33/204 C 805,947 12/1958 Great Britain 33/329 Primary Examiner-Robert B. Hull Attorney, Agent, or Firm.l. T. Cavender; George J. Muckenthaler; Wilbert Hawk, Jr.

[ Feb. 11, 1975 1. An artificial horizon gyroscope, comprising a frame, an attitude gimbal and roll-axis bearing means supporting said gimbal on a roll axis in said frame, said bearing means having a generally central passageway there thr9 ug l 1 display means including roll-indicating means connectmia said bearing means to indicate motion of said gimbal in roll, a gyro rotor assembly and bearing means supporting the same on a pitch axis in said gimbal, said display means including pitchindicating means having a pitch-transmitting linkage connection to said rotor assembly via the passageway in said roll-axis bearing means, said linkage including a transmitting arm pivotally supported by said gimbal on a pivot axis located between said pitch-axis bearing means and the passageway of said roll-axis bearing means, said arm extending through the passageway and supporting said pitch-indicating means, the opening of said passageway being such in relation to size and location of said arm as to permit pivoted movement of said arm through a range of direct pitchtransmitting connection to said rotor assembly corresponding to at least to a limited pitch range, and

said linkage including lost-motion connecting means operative to position said transmitting arm and said pitch-indicating means in accordance with pitch motion of said gimbal within said pitch range and to hold a maximum displaced position of said pitchindicating means for gimbal-pitch motion beyond said range.

PATENTEU 1 1915 3,864. 838 SHEET 2 OF 2 N w & w

INVENTO RS EQED JUWE/VS ARTIFICIAL-HORIZON GYROSCOPE This invention relates to instrumentation wherein two coordinate axial components of rotary displacement are to be monitored and displayed, as for example the pitch and roll components of airframe displacement with respect to a spinning gyro rotor assembly. The invention will be described in the specific context of an artificial-horizon gyroscope, sometimes known as an attitude gyro indicator.

Conventionally, an artificial-horizon gyroscope produces a roll-displacement indication, relying upon shaft rotation through the roll-axis bearing of the attitude gimbal; at the same time, pitch-displacement indications present a problem because the axis about which pitch is monitored, i.e., pitch of the gimbal with respect to the gyro-rotor assembly, about the pitch-axis bearing (or bearings), is offset or remote from the pivot axis or other reference used for pitch display. Various measures have been adopted to meet the problem, and the conventional approach is a pin-in-slot coupling, with the pitch-axis bearings pivoted between the pitchdisplay pivots and the pitch-display indication; but this approach is not particularly suitable in the context of pitch linkage within a rectangular attitude gimbal.

It is, accordingly, an object of the invention to provide an improved device overcoming the deficiencies of past constructions.

Another object is to meet the above objects with an inherently more rugged and more direct-acting mechanical construction.

A specific object is to provide an improved artificialhorizon gyroscope construction not requiring a cantilevered gimbal.

Another specific object is to provide such a construction in which full box-frame construction characterizes the attitude gimbal and its surrounding frame so that the gyro-rotor assembly can be cradled between accurately referenced spaced pitch-axis bearings and rollaxis bearings.

A further object is to provide, for such an instrument, a lost-motion pitch-transmitting linkage in which fullscale pitch display covers but a limited useful range of gimbal-pitch displacement and in which the displayed full-scale indication is held for gimbal-pitch displacements beyond this range.

A general object is to meet the above objects with direct-acting mechanism of elemental simplicity, ruggedness, and durability.

Other objects and further features of novelty and invention will be pointed out or will occur to those skilled in the art. from a reading of the following specification in conjunction with the accompanying drawings. In said drawings, which show. for illustrative purposes only, a preferred form of the invention:

FIG. I is a simplified plan view of the mechanism of an artificial-horizon gyroscope incorporating the invention, certain parts being broken and shown in longitudi' nal section;

FIG. 2 is a fragmentary sectional view at the plane 22 of FIG. 1; and

FIGS. 3, 4, and 5 are enlarged simplified views in elevation, showing linkage elements of FIG. 1, for various relative positions thereof.

Briefly, the invention contemplates an improved artificial-horizon gyroscope wherein the full scale of pitch display is but a fraction of the pitch-responsive range of the instrument. A simple linkage system includes a lost-motion connection to transmit gimbalpitch displacement with respect to the gyro rotor assembly, in such fashion (a) that the pitch-indicating element of the display is caused to indicate gimbal-pitch displacement only within the desired limited pitch range and (b) that a maximum-displaced position of the pitch-indicating element is held for gimbal-pitch motion beyond said range.

The instrument of FIGS. 1 and 2 is carried by a frame 10 and relies upon a gyro rotor assembly 11 as the basic reference from which roll and pitch rotational displacements of the frame 10 are picked-off for display at a dial or face region 12 at one end of the instrument. A two-axis gimbal suspension is employed for relating the assembly 11 to the frame 10; the roll axis is longitudinal and is designated 13, while the pitch axis is transverse and is designated 14. The gyro rotor assembly 11 may comprise a conventional electric or air-driven flywheel, encased in a housing, which may be the part to which pivoted supporting connections are made. The gyro rotor assembly 11 is shown in full lines for the attitude in which its spin axis 15 is perpendicular to the plane of the drawing; when twisted its longitudinal limits may appear as indicated by broken lines 16-16.

As shown,'a rectangular attitude gimbal 17 is the intermediate connection between the gyro rotor assembly 11 and the frame 10. In gimbal l7, longitudinal side members 18-18, on opposite sides of and in a plane common to the roll axis 13, rigidly connect end members 19-19 for generally rectangular integrity, and ball-bearing mounts 2020 secure the pitch-axis l4 connection of assembly 11 thereto. In similar fashion, the frame 10 is box-like or generally rectangular, comprising spaced longitudinal side members 21-21, on opposite sides of and in a plane common to the mean longitudinal attitude of the roll axis 13; side members 21-21 rigidly connect end members 22-22', and ball-bearing mounts 2323 secure the roll-axis 13 connection of gimbal 17 to frame 10.

Roll-axis 13 information may be transmitted to and displayed at 12 through conventional means. The roll display may include an outer ring or roll-index mask 25 positioned by an upper bracket 26 on a front pivot member 27; a background mask 28 is also shown to be positioned by a lower bracket 29, see FIG. 2, on the same front pivot member 27. Pivot member 27 has a central through-passage or bore 30 for accommodating linkage to be described, and it (member 27) is turned down at its reduced forward end in order to fit the bore of the inner ring of ball bearing 23. A spacer 31 offsets the support 32 (for brackets 26-29) from the inner ring of bearing 23, and a clamp plate 33 and screws 34 secure these rollindicating parts to the pivot ring 27. Thus, roll of gimbal 17 in frame 10 is directly transmitted via pivot ring 27 to the indicator masks 25-28.

In accordance with a feature of the invention, pitch information is directly and mechanically transmitted from within the gimbal 17 to the display face 12, being observable as an up-down pivoted displacement of a pitch-indicator mask 35. Mask 35 is at one end of a lost-motion linkage connection, via the throughpassage 30, to the gyro rotor assembly 11, and the displayed movement of mask 35 is about a pivot axis 36, at the forward end of gimbal 17 and parallel to the pitch axis 14. As shown, a pitch-arm or lever 37 has a central stem passing through opening 30. The forward end of this stem carries a bracket 38 by which the pitch mask 35 is positioned. At its other or base end, arm 37 includes a bridge 39 extending in opposite directions to position spaced feet 40 for pivotal connection on the axis 36; at each of the feet 40, a pivot cone 41 rides balls in a race recess and is externally accessible for lock-nut adjustment and fastening to gimbal 17. Fixed to and effectively forming part of the pitch arm or lever 37 is an extension or cam plate 42, see also FIGS. 3, 4, and 5, which moves in a radial plane about the pivot axis 36 and may be closely adjacent one of the side members (18) of the gimbal 17; another cam plate 43, fixed to and effectively forming part of the gyro rotor assembly 11, moves in a radial plane about the pitch axis 14 and may be closely adjacent to and overlapping with portions of cam plate 42. The lost-motion interconnection is completed by follower means or pins 44-45 carried by the respective plates 42-43; and the detailed nature of this connection will appear from a discussion of FIGS. 3 to 5.

In general, it should be observed that plates 42-43 are connected in direct rotary-to-rotary driving relation, about their axes 36-14, for a limited range of pitch displacements, which for the form shown amounts to 3 degrees with respect to the plane of axes 36-14. Over this range, their relation is one of straight-cam and follower, or of crank and follower link, and this range is displayed at 12 so as to run full scale, i.e., from a maximum of substantially 23 of pitch up, to a maximum of substantially 23 of pitch down. The particular engagement shown is one of pin-andslot, wherein the pin 45 on crank arm or plate 43 rides the straight slot 46 in the cam or following arm or plate 42; in FIG. 3, the gyro-spin axis 15 has been canted back 15, i.e., within the range fl3, and so pin 45 directly and positively locates in slot 46. For initial setup. the zero relation or mid-position of the pin-andslot engagement (45-46) may be set by a clamp screw 50 extending through a limited-arc slot 51 in plate 43.

It has been suggested above that plates 42-43 serve a cam or cam follower function. Such functions are operative in the lost-motion phase of the pitch linkage, i.e., in the range of gimbal pitch. about axis 14, beyond the limits of pin-and-slot engagement 45-46. The cam formation on crank plate 43 may be an arcuate profile 47, preferably a convex circular are about the pitch axis 14, and also preferably extending symmetrically in opposite directions from the location of pin 45. The cam formation 48 on plate or arm 42 is also preferably arcuate, the same being circular about the pitch axis 14 only when and after the pin-and-slot engagement 45-46 has reached an end; under such conditions (see FIG. 4), the pin-follower 44 has been displaced outwardly (of the pitch axis 14) to the point of engaging or locating the cam means 47 on the crank arm or plate 43. Thus, through a range of pitch motion beyond the limit of pin-and-slot engagement, the cams and followers 48-45 and 47-44 determine a fixed display of maximum pitch, while crank 43 goes through extended lost" pitch displacements. FIG. 4 shows the relationship when the gyro-spin axis 15 is canted 30, and wherein cam arm 42 is held at its maximum displaced position to display (at 35) the 25 maximum. FIG. shows an even further extreme pitch condition (spin axis canted 85), with cam and follower engagement at 47-44, to maintain the same display. Limit stops (not shown in FIGS. 1 and 2) may coact between gimbal 17 and one of the plates 42-43 to assure against loss of engagement 47-44, to and beyond the pitch condition, as will be understood; such stops, schematically indicated A-B-C-D in FIGS. 3 to 5, are seen to assure location of cam plate 42 in its extreme positions (stops A-B) and to assure against excessive displacement of the rotor assembly 11 (stops C-D).

Upon return to lesser degrees of pitch. the described engagements are retraced, and pin-and-slot engagement (45-46) is resumed in the :23" central region. It will be understood that for normal navigation and maneuvering, the i23 full-scale display is more than adequate, and that the need to display larger (and not useful) pitch angles beyond this range has been obviated. It will also be seen that by providing cam 43 on a sector which is laterally offset at 49, see also FIG. 1, from the remainder of plate 43, a second follower pin 44 on plate 42 may clear the crank plate 43 for all pitch angles involving reliance on pin 44, and that by providing a second arcuate cam 48' on plate 42, contiguous to the other side wall of slot 46, the described lost-motion relation applies for pitch angles canted in the opposite direction. In other words, by having cam 48' arcuate about pitch axis 14 for spin-axis slopes which are thenegative of those in FIGS. 4 and 5, the angular control of plate 42 about axis 36 will be the image of that already discussed.

The described mechanism will be seen to achieve the stated objects. More specifically, in addition to the magnified display of only the pitch range of interest. the invention provides improved support characteristics in the roll suspension by eliminating the cantilever construction generally used by the industry, in artificial-horizon gyro manufacture. The improved characteristics include better shock and vibration resistance, greater structural integrity due to the enclosed rectangular (as opposed to the conventional U-shape), better bearing alignments, and adaptability to future outsidein gyro horizon design.

While the invention has been shown and described for the preferred form shown, it will be understood that modifications may be made without departing from the scope of the invention.

What is claimed is:

1. An artificial horizon gyroscope, comprising a frame, an attitude gimbal and roll-axis bearing means supporting said gimbal on a roll axis in said frame, said bearing means having a generally central passageway therethrough, display means including roll-indicating means connected via said bearing means to indicate motion of said gimbal in roll, a gyro rotor assembly and bearing means supporting the same on a pitch axis in said gimbal, said display means including pitchindicating means having a pitch-transmitting linkage connection to said rotor assembly via the passageway in said roll-axis bearing means, said linkage including a transmitting arm pivotally supported by said gimbal on a pivot axis located between said pitch-axis bearing means and the passageway of said roll-axis bearing means, said arm extending through the passageway and supporting said pitch-indicating means, the opening of said passageway being such in relation to size and location of said arm to permit pivoted movement of said arm through a range of direct pitch-transmitting connection to said rotor assembly corresponding at least to a limited pitch range, and said linkage including lostmotion connecting means operative to position said transmitting arm and said pitch-indicating means in accordance with pitch motion of said gimbal within said limited pitch range and to hold a maximum displaced position of said pitch-indicating means for gimbal-pitch motion beyond said range.

2. A gyroscope according to claim 1, in which the pivotal axis of arm support is relatively proximate to the passageway of said roll-axis bearing means.

3. A gyroscope according to claim 1, in which said rotor assembly includes a crank arm forming part of said linkage, said arms having cam-and-follower engagement over a straight cam carried by one of said arms.

4. A gyroscope according to claim 3, in which said assembly includes selectively operable means for angularly adjustably positioning said crank arm with respect to the rotor axis of said assembly.

5. A gyroscope according to claim 3, in which said cam-and-follower engagement is a pin-and-slot engagement.

6. A gyroscope according to claim 5, in which the instantaneous location of pin-and-slot engagement is substantially mid-way between and in the plane containing both said pivotal axis and the axis of said pitch-axis bearing means when the slot is substantially aligned with said plane.

7. A gyroscope according to claim 5, in which the straight slot is on said transmitting arm and the pin is on the crank arm, said crank arm having an arcuate cam formation about the axis of said pitch-axis bearing means, and cam-follower means carried by said transmitting arm and engaging said arcuate cam formation beyond both limits of pin-and-slot engagement.

8. A gyroscope according to claim 3, in which the extent of said cam-and-follower engagement is over said limited pitch range, said straight cam-and-follower means being disengaged for gimbal-pitch displacements therebeyond, whereby full-scale pitch indications cover only said limited pitch range, said lostmotion means including means coaeting between said arms to retain the actuated maximum driven extent of said transmitting arm for crank-arm angular positions beyond the range of straight cam-and-follower engagement.

9. A gyroscope according to claim 8, in which said last-defined means includes an arcuate cam formation on said transmitting arm and cam-follower means on said crank arm, said cam formation being substantially arcuate about the axis of the pitch-axis bearing means when said transmitting arm has been displaced to one end of said limited pitch range, whereby cam engagement for the arcuate extent thereof enables free overriding pitch displacement of said gimbal while maintaining a maximum pitch indication by said display means.

10. A gyroscope according to claim 9, in which said transmitting arm includes a second arcuate cam formation which is substantially arcuate about the axis of the pitch-axis bearing means when said transmitting arm has been displaced to the other end of said limited pitch range, said second cam formation being engaged by said cam-follower means when said transmitting arm has been displaced beyond said other end ofthe limited pitch range.

11. A gyroscope according to claim 3, in which said crank arm includes a cam formation that is arcuate about the axis of said pitch-axis bearing means, and cam-follower means carried by said transmitting arm and operative to engage said cam formation at least through a range of angular lost motion beginning at and extending beyond a limit of said first-mentioned camand-follower engagement.

12. A gyroscope according to claim 11, in which said last-defined cam-follower means includes means further operative to engage said cam formation at least through a further range of angular lost motion extending beyond the other limit of said first-mentioned camand-follower engagement.

13. A gyroscope according to claim 3, in which both said arms include arcuate cam formations, both cam formations being arcuate about the axis of said pitchaxis bearing means for one limit of said first-mentioned cam-and-follower engagement, and means coaeting between said arms at said arcuate cam formations for retaining said arcuate cam formations in coaxial registry for crank-arm displacements beyond said limited-pitch range.

14. A gyroscope according to claim 13, in which said transmitting arm includes two such arcuate cam formations, respectively engageable with said last-defined means for crank-arm displacements beyond both limits of said first mentioned cam-and-follower engagement. =l l l l= Patent No. 5,86L 858 Dated Eebnuarl J] 1925 l Frederick J. Owens; Jerry B. Bishop It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On "information: page of issued patent, after listing of Primary Examiner and Attorneys, delete claim 1 in its entirety and insert therefor the "Abstract of the Disclosure", which was submitted with the original application, and minor amendments thereto.

ABSTRACT OF THE DISCLOSURE The invention contemplates an improved artificialhorizon gyroscope wherein the full scale of pitch display is but a fraction of the pitch-responsive range of the instrument. A simple linkage system includes a lost-motion connection to transmit gimbal-pitch displacement with respect to the gyro rotor assembly, in such fashion (a) that the pitch-indicating element of the display is caused to indicate gimbal-pitch displacement only within the desired limited pitch range and (b) that a maximum-displaced position of the pitch-indicating element is held for gimbal-pitch motion beyond said range.

Signed and sealed this 10th day of June 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks 

